Technology Description

XSVE is the extension of SVE to specifically address 1,4-dioxane contaminated soil. Conventional SVE is often the remediation technology of choice for the chlorinated solvents typically found with 1,4-dioxane. SVE is known to remove some 1,4-dioxane, but substantial residual is usually left behind. This is because, although 1,4-dioxane has a vapor pressure in the same range as trichloroethene (TCE) or benzene, it is much more water-soluble, resulting in preferential partitioning into pore water rather than vapor. Existing site data show that although some 1,4-dioxane removal occurs during conventional SVE, cleanup is incomplete. XSVE solves this problem through a combination of increased air flow, sweeping with drier air, increased temperature, decreased infiltration, and more focused vapor extraction. All of these enhancements may not be required at every site. The enhancements address the impact of pore water on 1,4-dioxane relative to remediation success. Conventional SVE typically requires extraction of between 200 and 5,000 pore volumes and operation from 2 to 4 years. Without the XSVE enhancements, orders of magnitude more pore volumes would be required to remove significant 1,4-dioxane mass. Injection of drier air near the extraction point reduces required pore volumes to achieve closure; heating the injected air and soils increases the removal of both water and 1,4-dioxane. Heated air reduces air injection closer to that of conventional SVE.